UV STABLE FIRE-RESISTANT GLAZING LAMINATES

Abstract

This specification generally relates to aqueous compositions for preparing UV stable fire-resistant interlayers. It also relates to UV stable fire-resistant glazing laminates comprising such interlayers, the use of such glazing laminates in construction, and constructions comprising such glazings. An example aqueous composition comprises a mixed alkali metal silicate of general formula SiO.sub.2.M.sub.2O, where M is K or Na, and other organic and inorganic additives. Glazings with interlayers made with such aqueous compositions are simple to prepare and demonstrate good UV stability and fire-protection properties.

Claims

1. An aqueous composition for preparing a castable UV-stable fire-resistant interlayer, comprising: a mixed alkali metal silicate of general formula SiO.sub.2.K.sub.2O.M.sub.2O, where: M is Li and/or Na, the weight ratio of SiO.sub.2:K.sub.2O is between about 2.5:1 and about 4.0:1, and the weight ratio of SiO.sub.2:M.sub.2O is between about 2.2:0.1 and about 4.5:0.1; about 0.5% w/w-about 5% w/w of a hydroxylated amine compound and/or quaternary ammonium salt; about 10% w/w-about 20% w/w of a polyhydric organic compound; and about 15% w/w-about 35% w/w water.

2. An aqueous composition as claimed in claim 1 where M is Na.

3. An aqueous composition as claimed in claim 2 where the weight ratio of SiO.sub.2:K.sub.2O:Na.sub.2O is between about 2.5:1:0.1 and about 3:1:0.1.

4. An aqueous composition as claimed in claim 3 where the weight ratio of SiO.sub.2:K.sub.2O:Na.sub.2O is about 3:1:0.1.

5. An aqueous composition as claimed in claim 1 comprising between about 0.01% w/w-about 5% w/w of a water-soluble aluminate.

6. An aqueous composition as claimed in claim 5 where the water-soluble aluminate is sodium aluminate in an amount of about 0.01% w/w-about 0.1%.

7. An aqueous composition as claimed in claim 1 where the hydroxylated amine compound and/or quaternary ammonium salt is selected from ethanolamine and tetramethyl ammonium hydroxide.

8. An aqueous composition as claimed in claim 1 where the polyhydric organic compound is selected from xylitol and glycerol.

9. An aqueous composition as claimed in claim 8 where the polyhydric organic compound is a mixture of xylitol and glycerol.

10. An aqueous composition as claimed in claim 1 where the amount of water is between about 27% w/w-about 33% w/w.

11. An aqueous composition as claimed in claim 1, comprising: a mixed alkali metal silicate of general formula SiO.sub.2.K.sub.2O.M.sub.2O, where M is Na and the weight ratio of SiO.sub.2:K.sub.2O:Na.sub.2O is about 3:1:0.1; about 0.01% w/w-about 0.1% w/w sodium aluminate; about 0.5% w/w-about 5% w/w ethanolamine; 0% w/w-about 10% w/w of xylitol; about 10% w/w-about 20% w/w of glycerol; and about 15% w/w-about 35% w/w water.

12. An aqueous composition as claimed in claim 1, comprising: a mixed alkali metal silicate of general formula SiO.sub.2.K.sub.2O.M.sub.2O, where M is Na and the silicate comprises: about 25% w/w-about 45% w/w SiO.sub.2, about 5% w/w-about 20% w/w K.sub.2O, and about 0.5% w/w-about 3% w/w Na.sub.2O; about 0.01% w/w-about 0.1% w/w sodium aluminate; about 0.5% w/w-about 5% w/w ethanolamine; 0% w/w-about 10% w/w of xylitol; about 10% w/w-about 20% w/w of glycerol; and about 15% w/w-about 35% w/w water.

13. An aqueous composition as claimed in claim 1, comprising: an alkali metal silicate of general formula SiO.sub.2.K.sub.2O.M.sub.2O, where M is Na and the silicate comprises: about 30% w/w-about 40% w/w SiO.sub.2, about 10% w/w-about 15% w/w K.sub.2O, and about 0.5% w/w-about 1.5% w/w Na.sub.2O; about 0.1% w/w sodium aluminate; about 1% w/w ethanolamine; 0% w/w-about 6% w/w of xylitol; about 10% w/w-about 16% w/w of glycerol; and about 15% w/w-about 35% w/w water.

14. An aqueous composition as claimed in claim 1, comprising: an alkali metal silicate of general formula SiO.sub.2.K.sub.2O.M.sub.2O, where M is Na and the silicate comprises: about 40% w/w SiO.sub.2, about 14% w/w K.sub.2O, and about 1.3% w/w Na.sub.2O; about 0.1% w/w sodium aluminate; about 1% w/w ethanolamine; about 16% w/w of glycerol; and about 28% w/w water.

15. A process for the preparation of an aqueous composition, the process comprising: (a) preparing a silica solution by mixing a suitable silica source with a hydroxylated amine compound and/or quaternary ammonium salt and a polyhydric organic compound in water; (b) optionally reducing the water content of the silica solution; (c) preparing an alkali metal hydroxide solution by mixing potassium hydroxide, lithium hydroxide and/or sodium hydroxide in water; (d) mixing the silica solution and the alkali metal hydroxide solution together; and, optionally; (e) heating the mixture until the reaction is complete.

16. (canceled)

17. (canceled)

18. A glazing laminate comprising: a first pane and a second pane; and a fire resistant interlayer between the first pane and the second pane, wherein the fire-resistant layer is prepared by curing an aqueous composition as claimed in claim 1.

19. A glazing laminate as claimed in claim 18, where the first pane and the second pane consist of float glass.

20. A glazing laminate as claimed in claim 18, where the first pane and the second pane have a thickness between about 1.5 mm and about 5 mm and the fire-resistant interlayer is between about 0.5 mm and about 5 mm in thickness.

21. (canceled)

22. (canceled)

23. (canceled)

Description

FIGURES

[0858] FIG. 1 shows the cross-section of an example glazing laminate in an about 3 mm width/1 mm width/3 mm width pane/interlayer/pane configuration (a “3/1/3 construction type laminate”).

[0859] FIG. 2 shows the cross-section of an example glazing laminate in a 3/1/3/1/3 construction type laminate.

[0860] FIG. 3 shows the cross-section of an example glazing laminate in a 3/1/3/1/3/1/3 construction type laminate.

[0861] FIG. 4 shows the cross-section of an example glazing laminate in a 3/1/3/1/3/1/3/1/3/1/3 construction type laminate.

[0862] FIG. 5 shows the UV stability testing results for a range of interlayer compositions.

[0863] FIG. 6 shows the char-flow melt of interlayers comprising different compositions of alkali metal silicate.

DETAILED DESCRIPTION

[0864] Preparation of Aqueous Compositions

[0865] An example aqueous composition for preparing a fire-resistant interlayer according to the claims was prepared as a two-component mix. The first component was prepared by mixing a silica sol (Levasil® CS50-34P 50/50 w/w aqueous; 82.3% w/w) with glycerol (99.5% purity, 16.6% w/w) and ethanolamine (99% purity, 1.1% w/w). This mixture was distilled in order to reduce the water content to 11%. The second component was made by mixing potassium hydroxide (50% aqueous solution, 89.1% w/w), sodium hydroxide (50% aqueous solution, 7.8% w/w) and sodium aluminate (40% aqueous solution, 3.1% w/w). The two component solutions were then added together in the proportions 65.66% w/w silica sol mix to 34.34% w/w basic hydroxide mix. The components were vigorously mixed under reduced pressure while controlling the temperature below 60° C. in order to avoid evaporation or a runaway reaction. Finally, the mixture was heated at 50° C. for 30 minutes then rapidly cooled to approximately 25° C., retarding further reaction.

[0866] Various aqueous compositions with the desired properties were prepared according to this basic method. They are shown in Table 1. Asterisked Examples are for reference only, and do not form part of the invention.

TABLE-US-00001 TABLE 1 Example Aqueous Compositions for Preparing Fire-resistant Interlayers w/w % w/w % w/w % w/w % w/w % w/w % w/w % w/w % Wt. ratio Composition H.sub.2O SiO.sub.2 NaAl.sub.2O.sub.3 Ethanolamine Xylitol Glycerol Na.sub.2O K.sub.2O SiO.sub.2:K.sub.2O:Na.sub.2O A* 46.5 35.2 0 0 0 4.5 0 12.8 2.9:1:0 B* 47 31.0 0.19 2.0 0 3.9 0 12.2 2.5:1:0 C 29.5 37.6 0 1.2 5.8 10.5 0.9 13.1 2.9:1:0.07 D 29.5 37.5 0 1.2 5.8 10.4 0.9 13.1 2.9:1:0.07 E 32 37.1 0.14 1.1 5.7 10.3 0.9 13.0 2.9:1:0.07 F 32 35.7 0 1.1 5.5 9.9 0.9 12.5 2.9:1:0.07 G 32 35.7 0 1.1 5.5 9.9 0.9 12.5 2.9:1:0.07 H 32 37.3 0 1.0 0 12.5 1.1 15.0 2.5:1:0.07 I* 31.5 38.0 0.07 1.0 0 15.0 6.3 7.1 5.4:1:0.88 J 32.5 36.8 0.08 1.0 0 14.8 1.3 12.9 2.9:1:0.10 K 32.5 31.5 0.08 1.0 0 15.0 1.4 12.8 2.5:1:0.11 L 32.5 36.8 0.08 1.0 0 14.8 1.3 12.9 2.9:1:0.10 M 32.5 36.8 0.08 1.0 0 14.8 1.3 12.9 2.9:1:0.10 N* 32.5 38.0 0 1.0 0 15.0 6.4 7.1 5.3:1:0.90 O 32.5 36.8 0.08 1.0 0 14.8 1.3 12.9 2.9:1:0.10 P 32.5 36.8 0.08 1.0 0 14.8 1.3 12.9 2.9:1:0.10 Q 32.5 36.5 0.15 1.0 0 14.7 1.3 12.9 2.8:1:0.10 R 32.5 37.2 0.07 1.0 0 15.0 1.3 12.3 3:1:0.10 S 32.5 36.8 0.08 1.0 0 14.8 1.3 12.9 2.9:1:0.10 T 28.5 39.4 0.08 1.1 0 15.9 1.3 13.7 2.9:1:0.10 U 28.5 39.4 0.08 1.1 0 15.9 1.3 13.7 2.9:1:0.10 V 28.5 39.4 0.08 1.1 0 15.9 1.3 13.7 2.9:1:0.10 W 28.5 39.4 0.08 1.1 0 15.9 1.3 13.7 2.9:1:0.10 X 28.3 39.4 0.08 1.1 0 15.9 1.3 13.7 2.9:1:0.10 Y* 28.3 39.4 0.08 0 0 17.0 1.3 13.7 2.9:1:0.10 Z* 46.5 35.2 0 0 0 4.5 0 12.8 2.9:1:0 AA 26.3 40.6 0.08 1.1 0.0 16.3 1.3 11.3 2.9:1.0:0.1 AB 21.0 45.5 0.06 1.2 0.0 18.3 1.6 12.1 3.8:1.0:0.1

[0867] Preparation of Glazing Laminates

[0868] A glazing laminate featuring a fire-resistant interlayer according to the claims was prepared from the above aqueous compositions as follows. The aqueous composition was poured or pumped between two float glass sheets held apart by a spacer or seal, and cured by gentle heating (for example for 24 hrs at 85° C.) to produce the required laminate.

[0869] Various configurations of glazing laminate can be constructed according to this basic technique. For example, a “3/1/3 construction type” has two panes (for example of float glass) each of about 3 mm thickness, sandwiching an approximately 1 mm thickness interlayer (see FIG. 1, where dimensions shown under picture are in mm).

[0870] Similar configurations of alternating about 3 mm thickness pane and about 1 mm thickness interlayer can also be used, forming more complex glazing laminates. For example, a 3/1/3/1/3 construction type has a total of 3 panes of about 3 mm thickness alternating with two interlayers of 1 mm thickness (see FIG. 2). A 3/1/3/1/3/1/3 construction type has a total of 4 panes of about 3 mm thickness alternating with three interlayers, all interlayers being similarly enclosed by glass (FIG. 3). A 3/1/3/1/3/1/3/1/3 construction type uses the same alternating structure (FIG. 4), and so on.

[0871] Different thicknesses of glass and interlayer can also be used to prepare suitable glazing laminates, for example in a 3/1.1/3, 3/1.1/3/1.1/3, 3/1.1/4/1.1/3, 3/1.6/3/1.6/3/1.6/3, 3/1.6/3/1.6/3/1.6/3/1.6/3/1.6/3, 4/1/4, 4/2/4, 5/3/5, 2.82.8/1.1/2.8, 2.8/1.1/2.8/1.1/2.8, 2.8/1.1/4/1.1/3, 2.8/1.6/2.8/1.6/2.8/1.6/2.8, 2.8/1.6/2.8/1.6/2.8/1.6/2.8/1.6/2.8/1.6/2.8, 4/1/4, 4/2/4 or 5/3/5 arrangement, although other possible arrangements will be apparent to a person skilled in the art.

[0872] The figures show example laminates described in this specification. In the figures, 1 is a sheet or pane of glass (for example float glass) and 2 is fire-resistant interlayer as embodied herein. Numerals at the bottom of the figures are in mm.

[0873] Testing Protocols

[0874] Viscosity/pourability testing was carried out qualitatively by attempting to pour the aqueous compositions into the internal space of a preconstructed glazing laminate template formed of two panes held together with a spacer or seal. Suitable compositions were seen to flow freely into the internal space of the glazing laminate precursor without the formation of an excess of bubbles, meaning they were amenable to casting. Compositions with a very high viscosity (e.g. Example Y) were not castable.

[0875] UV Stability testing was carried out according to EN 12543-4-2011 which specifies test methods in respect of resistance to high temperature, humidity and radiation for laminated glass and laminated safety glass for use in building. The UV test performed was of 2000-hour duration. At the end of the test, plates were visually inspected for bubble formation, with few or no bubbles leading to a positive result. FIG. 5 shows the UV stability of a range of interlayers correlated with percentage sodium.

[0876] Glazing laminate fire tests were carried out according to publicly available European standards EN1364-1:2015 and EN1363-1:2012.

TABLE-US-00002 TABLE 2 Example Glazing Laminates and Test Results Viscosity of Thickness of EN1353 Fire EN1353 Fire Composition Glazing Unit Construction Test result Test Result UV Composition on Pouring (mm) Type (Integrity E) (Integrity EI) Stable A* low 9 4/1/4 <15 NR Yes B* low 7 3/1/3 16 NR Yes C high 7 3/1/3 45 NR Yes D high 11 3/1/3/1/3 70 NR Yes E medium 7 3/1/3 60 — Yes F medium 7 3/1/3 52 — Yes G medium 11 3/1/3/1/3 56 Yes H medium 7 3/1/3 50 — Yes I* high 7 3/1/3 40 NR No J low 7 3/1/3 35 — Yes K medium 7 3/1/3 40 — Yes L low 11 3/1/3/1/3 67+ .sup.1 — Yes M low 11 3/1/3/1/3 61+ .sup.1 — Yes N* med 7 3/1/3 53 NR No O low 11 3/1/3/1/3 50 — Yes P low 15 3/1/3/1/3/1/3 52 37 Yes Q low 11 3/1/3/1/3 51 — Yes R low 11 3/1/3/1/3 30 — Yes S low 11 3/1/3/1/3 39 — Yes T medium 7 3/1/3 45 — Yes U medium 11 3/1/3/1/3 109 — Yes V medium 11 3/1/3/1/3 72+ .sup.1 — Yes W medium 11 3/1/3/1/3 67+ .sup.1 — Yes X medium 25 3/1/3/1/3/1/3/1/3/1/3 71+ .sup.1 66 Yes Y* very high 11 3/1/3/1/3 — — Yes Z* low 10 4/2/4 2 NR Yes AA medium 7 3/1/3 — — Yes AB high 7 3/1/3 — — Yes .sup.1 Terminated without failure.

[0877] High temperature char-flow melt tests were adapted from known glaze melt fluidity tests using readily available materials. A piece of vermiculite board 100 mm×200 mm×25 mm had one short edge chamfered at 45° and a hole (diameter 25 mm, depth 10 mm) drilled in each corner of the opposite end, 10 mm from each edge, so that when the board was stood on the chamfer to form a 45° slope the holes were on the top face. To compare the char-flow two different silicates interlayer materials, a disc of the silicate (diameter 25 mm and thickness 5 mm) was placed into each hole. The vermiculite board was placed flat in a furnace with the holes uppermost and heated in stages to 90° C., 150° C., and 1000° C., leaving it for approximately 15 minutes at each temperature, so that all water is driven off leaving the silicate as a collapsed melt. The test boards were then cooled and inclined to 45° using a support. The furnace was then reheated to 1000° C. and left for several hours for the silicates to melt and flow down the slope. Three hours was generally found to be enough time to differentiate flow rates, though this differed for individual samples. After this time the furnace was turned off, the test board cooled, and the relevant measurements made.

[0878] The results of the char-flow experiments are shown in FIG. 6. The three plates in the figure show the char flow of various mixed sodium and potassium silicate-based interlayers when placed in the circular gap and subjected to the fire test. In each plate the amount of sodium relative to potassium increases from left to right across the plate, and the left-most hole represents an interlayer with only potassium silicate present and no sodium silicate. It can be seen that as levels of sodium silicate increase with respect to potassium silicate, the flow of the molten char is reduced. This helps the mixed alkali metal silicates described in this specification maintain the coverage and integrity of the interlayer during a fire, improving the fire-resistant properties of its parent laminate or glazing unit.